Reciprocating pumps utilized with oil wells are usually operated through a sucker rod system wherein a plurality of elongated steel rods are interconnected by threaded fittings, the lower end of the sucker rod string being attached to the pump piston, while the upper rod end is affixed to an oscillating pump arm. Sucker rods consisting of a plurality of interconnected metal rods are heavy, requiring relatively high energy to lift, are troublesome to install and remove as adjacent rods must be interconnected or disassembled as the rod system is inserted or removed, and the frictional coefficient of friction of conventional sucker rod systems is relatively high due to the presence of the fittings.
It has been proposed to replace the conventional multi-segment pumping or sucker rod systems with a single rod which extends the depth of the well. Single strand sucker rod systems utilizing metal rods are known wherein the rod is stored upon a reel. Also, a pumping rod system utilizing a single glass fiber rod is known as shown in U.S. Pat. No. 3,889,579.
Single strand sucker rod systems have not been utilized to an appreciable extent even though the same have definite advantages over multi-strand rod systems with respect to cost of manufacture, cost of installation and removal, and low frictional and weight characteristics. Such rod systems have not been widely accepted primarily due to the difficulty in handling and installing the rod, and removing the rod from the well. The glass fiber sucker rod disclosed in U.S. Pat. No. 3,889,579 has not been commercially feasible due to the inability of efficiently handling the rod and inserting and removing the rod with respect to the well.
It is an object of the invention to provide a sucker rod system for oil wells utilizing a continuous glass fiber rod wherein the rod is efficiently handled, stored and transported in such a manner as to protect the rod against damage, and yet permit ready dispensing and retrieval.
A further object of the invention is to provide a sucker rod system for oil wells utilizing a glass fiber rod wherein the rod is stored upon a reel and is readily dispensed from or rewound thereon.
Yet another object of the invention is to provide a sucker rod system for oil wells utilizing a glass fiber sucker rod wherein the rod is stored and transported on a reel having a substantially horizontal axis and power means are utilized to draw the rod from the well and store the rod on a reel.
Yet another object of the invention is to provide a sucker rod system for oil wells utilizing glass fiber rod wherein the rod is stored and transported on a reel having a substantially horizontal axis and rod support means are employed at transition zones as the rod changes between horizontal and vertical orientation between stored and use conditions.
An additional object of the invention is to provide a sucker rod system for oil wells utilizing a glass fiber rod which employs an endless friction traction drive apparatus for installing and removing the rod from a well.
Another object of the invention is to provide a fitting for use with glass fiber sucker rods wherein the fitting is capable of exerting high tension forces upon the rod without failure to the rod or fitting.
An additional object of the invention is to provide a sucker rods retrieval tool for use with glass fiber rods permitting broken rod to be readily removed from a well.
In the practice of the invention, the pump or sucker rod for an oil well is coiled upon a large reel and dispensed therefrom, or wound thereon when not located within a well. Preferably, the rod for a well consists of a single length of glass fiber rod formed of a plurality of elongated glass filaments embedded within a resin. In one embodiment of the invention the reel is power operated, while in another embodiment a drive mechanism directly associated with the rod provides the force for uncoiling or coiling the rod upon the reel.
The reel has a substantially horizontal axial orientation, and the rod is dispensed from the reel in a substantially horizontal manner. At the transition zone wherein the rod passes from a horizontal orientation to a vertical relationship at the well, support means are provided to prevent the rod from being bent to an extent which might cause fracturing of the rod or separation of the filaments within the resin.
The system of the invention also includes a fitting attached to the ends of the rod to which the usual pumping apparatus may be connected through threaded components, and the fitting is of such nature that interconnection between the fiting and rod increases proportional to the tension forces being transmitted.
Additionally, the system includes a retrieval tool for "fishing" broken glass fiber rod from a well, and the retrieval tool automatically grips the rod upon a lifting or tension force being applied.